If you plan on doing electronics, you need to learn to read a data sheet. You can find it here: http://www.sparkfun.com/datasheets/Comp ... HRJ00F.pdf
You can find a tutorial on how to read a datasheet in the Sparkfun tutorial section.
On page two you will see the internal schematic. One set of pins if for the LED and the other for the transistor used as a switch.
Pin 1 will go to 5V.
Pin 2 will go to a resistor.
The other end of that resistor goes to ground.
From the table on page 4, you will see the forward voltage is about 1.14V at 7ma. That means the resistor need to be (5-1.14)/(.007) or 551 ohms. But since the LED can go up to as much as 50ma a standard 330 ohm resistor should do just fine.
Now the transistor side is even simpler.
Pin 3 goes to 5V
Pin 5 goes to ground
Pin 4 goes to a digital input pin on the Arduino.
Edit: Deadline has come and gone and no reply from OP. Why does this continue to surprise me...?
Edit: Any news on this? I hate threads that just end without resolution...